Many things could be wrong. There are too many variables to speculate. Please get in to see a healthcare provider.
This can possibly be an infection or even an IUD issue or even an ovarian issue! Maybe internal vaginal damage as well due to daily sex.
So, just having an IUD removed can skew your hormones and bleeding after irregularly is common. Are the cramps like period cramps? My suggestion is to go ahead and see your doctor that removed the IUD for examination AND to talk about the next type of birth control to get on since you may need that having sex every day. And you do not get internal damage from every day sex, just want to get that out there. :>) Take care and let us know what your doctor says!